Catamarans



ea. 22, 1959 c. F. GUNDERSON 2,917,754

GATAMARANS Filed Dec. 27, 1955 3 Sheets-Sheet 1 FIG. 2 4| 1959 c. F.GUNDERSON 2,917,754

CATAMARANS Filed Dec. 27, 1955 s Sheets-Sheet 2 Dec. 22, 1959 c. F.GUNDERSON 2,917,754

CATAMARANS Filed Dec. 27, 1955 :s Sheets-Sheet s QATAMARANS Charles F.Gnnderson, West Belmar, NJ.

Application December 27, 1955, Serial No. 555,606

14 Claims. (Cl. 9-2) Catamarans have always been recognized as outstanding watercraft. Because of their relatively large beamto-length ratio,they are seaworthy, stable and highly resistant to capsize. However thisrelatively large beam, which is so advantageous when the craft arewaterborne, is a serious handicap when the craft are moved ashore. Theyare then clumsy, bulky and difficult to handle. Many catamarans havebeen so constructed that their hulls and central deck are substantiallyrigid relative to each other. To achieve this rigidity, extra structureis necessary, thereby increasing the cost and weight of the craft, andalso reducing seaworthiness. Catamarans have always been notoriouslydifficult to bring about when changing tack. The invention described inthe present specification has been designed to overcome these drawbacksof other catamarans.

It is an object of the present invention to provide a watercraft of thecatamaran type wherein the hulls and the deck have a sufficient degreeoffiexibility relative to each other to permit the craft to conform tothe movements of the water. This resilience built into the craft acts asa shock absorber and makes the craft more seaworthy. It also makes forsavings in weight and cost. Sailing qualities are enhanced because jarsto the mast, which would spill wind from the sails, are reducedconsiderably. The lighter construction not only increases buoyancy, whenin the water, but it simplifies the hairdling of the craft when out ofthe water.

It is another object to provide such a craft which has its hulls coupledto its deck in such a manner that the hulls may be folded over the deck,or they may be separated from the deck, to facilitate storage andhandling of the craft when out of the water.

Still another object is to construct hulls largely without frames orribs generally used in conventional boat construction. In this way bothweight and cost are reduced and sailing speed is increased.

Yet another object is to provide a sailing craft without a centerboardor leeboards, thereby again reducing weight and cost. As a result theleaks notoriously present in centerboard wells are eliminated, the dragof a centerboard or leeboards is removed and, not least, the draft isreduced so drastically that the craft may sail in many waters notavailable to conventional sailing craft.

Other objects will become apparent from the following specification andthe appended drawing, wherein;

Figure 1 is a starboard side elevation of a folding catamaran embodyingmy present invention, shown in its opened operating waterbornecondition, except that, only for purposes of illustration, the starboardaft outrigger is shown in its retracted, longitudinally disposed,position, to which it is swung to permit folding of the catamaran;

Figure 2 is a plan view of the catamaran of Figure 1, the starboard aftoutrigger likewise being shown in its retracted position as in Figure 1;

Figure 3 is a composite view, the starboard portion of the craft (shownto the left in the figure) being a 1' atenti ice how elevation, and theport portion being shown in section along the line 3-3 of Figure 2;

Figure 4 is an enlarged fragmentary sectional view, also taken along theline 33 of Figure 2, showing details of the starboard hull and forwardoutrigger;

Figure 5 is a stern elevation of the catamaran in its partly foldedcondition, with the Outriggers retracted and one hull swung over thedeck;

Figure 6 is a starboard elevational view of the catamaran, folded and ontop of a motor vehicle; and,

Figure 7 is a sectional view, taken along the line 7--7 of Figure 6, butto a larger scale than Figure 6.

I attain the objects set forth above preferably by building the hullsand deck assembly largely of plywood (although I do not wish to limitmyself to that material), thereby achieving strength and lightness.Strength in each hull is further obtained by maintaining the plywood inarcuate configeration. I eliminate frames in the normal sense, butnevertheless achieve suitable strength by providing gunwale coamings andOutriggers, which cooperate to take the place of frames, while alsoserving their other functions.

I obtain flexibility by using a panel of plywood in the deck assembly,thereby permitting the hulls to move independently of each other withindesired limits. Such flexibility insulates the craft from considerablestrains inherent in rigid catamarans referred to above.

I obtain foldability by hinging the hulls to the opposite sides of thedeck assembly and providing releasable means which secure the bulls intheir unfolded operating positions, but which may be released to permitthe hulls to be folded over the deck, as for storage or portage.

I-prefer V bottom hulls for simplicity of construction and speed throughthe water. However, I make them asymmetricaLso that one side of the V isvertical, or at least sufficiently vertical so that it functions as acenterboard or leeboard.

I also raise the forward and aft ends of each hull out of the water, orat least reduce the draft at the ends of each hull sufficiently, topermitthe craft to come about readily when changing tack. I furtherimprove the crafts ability to come about by providing it with a longsweep type rudder, so supported that it can be operated like an oar toreadily spin the craft as desired.

Referring now more specifically to the drawing, the preferred embodimentof my invention illustrated is made up of three main parts, namely, adeck assembly 11, a port hull 13 and a starboard hull 15.

The deck assembly 11 includes a deck 17 which is preferably a panel ofplywood, or other suitable sheet material, having a fair degree offlexibility. Secured lengthwise to the under surface of the deck 17 area pair of spaced parallel longitudinal stringers 19 which add a desiredamount of stifiness to the deck 17, in a fore and aft direction, andalso act as supports upon which the catamaran may stand when it isstored or is being transported (as on racks 20 on top of a car 22).Secured to the upper surface of the deck 17 are a pair of spacedparallel transversely positioned cross braces 21. The catamaran isprovided with four Outriggers 24, two of which are swingably secured toeach cross brace 21, by means of a pair of pivot bolts 23. Eachoutrigger 24 may be swung to its extended operating position, inalignment with the cross brace 21 (three outriggers being so illustratedin Figure 2), or it may be swung inwardly to its retracted, or folded,position, lengthwise of the deck assembly 11 (the starboard aftoutrigger being so illustrated in Figures 1 and 2). The under side ofthe deck 17 may also be provided with a central longitudinal stringer 25to give the forward end of the deck an additional degree of strengthwhere 'it supports a mast 27.

The deck 17 may also be provided with an outboard 3 rack 29 at its aftend. Preferably a central section 30, of the aft end of the deck 17, isbent downwardly at a slight angle to form an outboard well between thetwo stringers 19. The outboard rack 29 forms the aft end of thisoutboard well. I provide the outboard rack 29 with an oarlock 28 whichmay receive a sweep rudder 32. This rudder 32 may take the form of aconventional car. The forward end of the deck 17 may also be fitted witha pair of forwardly slanting spray shields 31.

For simplicity of construction and reduction in cost, the hulls 13, 15are preferably duplicates of each other. Hence only the port hull 13will be described at this point. Said hull 13 includes a keel 33, whichis preferably triangular in cross section. Secured to adjacent surfacesrespectively of the keel 33 are an inboard planking panel 35 and anoutboard planking panel 37, both being of plywood or other sheetmaterial. Each end of the hull 13 terminates in a V-shaped or triangulartransom 39. As may be seen in Figure 1, the lower edge of each of theplanking panels 35, 37 is arcuate, thereby bringing the fore and aftends of the hull 13 out of the water, or at least effecting a reduceddraft at both ends. It will be understood that the degree of arc is acomprise to achieve a suitable degree of speed and fore and aftstability, on the one hand (both of which characteristics are enhancedby a large radius of arc), and an ability of the craft to come about, onthe other hand (which is enhanced by a lesser radius of arc).

In order to strengthen the hull 13, where it is hinged to the deckassembly 11, an inboard sheer strake 41 is provided at the upper edge ofthe inboard planking panel 35. The inboard sheer strake 41 is preferablya relatively stiff member and is provided with an arcuate lower edge 43and a straight upper edge 45. The upper edge 45 is preferablypositioned, when the craft is waterborne, immediately below one edge ofthe deck 17 and it acts to support and stiffen the edge of the deck (seeFigs. 1 and 4). The upper edge of the outboard planking panel 37 ispreferably provided with a gunwale coaming 47. i

The hull 13 is pivotally secured to the deck assembly 11 by a pair ofloose-pin hinges 49. Each hinge 49 is secured to the deck assembly 11 atthe outer end of a cross brace 21 and is secured to the hull 13 atthe'inboard sheer strake 41. The loose pins of the hinges 49 permit thehull 13 to be removed from the deck assembly 11 as desired and alsosimplifies the building of the craft and the step of coupling the hulls13, 15 to the deck assembly 11. Each outrigger 24 is provided at itsouter end with suitable means to secure it to the gunwale coaming 47,when the craft is in its operating waterborne position. Preferably Iprovide the outer end of each outrigger 24 with a protruding metal eye51 (as illustrated in Figures 2 and 4). The gunwale coaming 47 ispierced by a slot 53 to receive the eye 51. A pin 55 is provided to passthrough a hole in the coaming 47 and the hole of the eye 51, to therebylock the outer end of the outrigger 24 to the hull 13. A metal strikeplate 56 (see Figures 2 and 4) may be secured to the inside of the hull13 at each of the two slots 53. Each strike plate 56 strengthens thehull 13 where it receives the eye 51 of one of the outriggers 24 and italso protects the wood of the hull from being scratched by the eyeduring folding or unfolding of the craft. Each strike plate 56 ispierced by a slot 54, in register with its associated slot 53.

The starboard hull 15 is a duplicate of the port hull 13 just describedand it is pivotally secured to the deck assembly 11 in the same manner.

When the parts are assembled in their operating positions, as shown inFigures 1-4, the outriggers 24 hold the hulls 13, 15 in such positionsthat the boat is a unitary integrated operating structure. The matingsurface between the cross braces 21 and the outriggers 24 should be aslong as possible in an athwartship direction, so as to maintain thedesired relatively rigid alignment between each of the cross braces 21and its outriggers 24. Nevertheless the catamaran illustrated may bereadily and instantaneously folded by merely releasing the four pins 55,swinging the four outriggers 24 inwardly and swinging the two hulls 13,15 inwardly over the deck 17, one at a time (as illustrated in Figure5), so that one nests partly within the other (as illustrated in Figures6 and 7).

The mast 27 is of the type that may be separated into two pieces (notshown) to permit storage within the folded catamaran. The mast may besupported by stays (not shown), in conventional fashion, or it may beotherwise supported, as by a tripod 57. If a tripod 57 or the like isused, it should be of such a size and structure that it will notinterfere with the folding and unfolding of the craft. More particularlyit should not interfere with the swinging of the outriggers 24 and itshould fit within the hulls 13, 15 when they are in their folded nestedpositions, as shown in Figures 6 and 7. It will then be possible to foldor unfold the hulls 13, 15 quickly with the tripod 57 in place.

If the catamaran, in its folded condition, is to be carried, some meansshould be provided to keep the hulls 13, 15 from swinging upwardly. Thiscan be accomplished for example by merely tying a rope 59 completelyaround the folded craft (as illustrated in Figures 6 and 7).

It will now be seen that my catamaran is an unusual but useful craft.When opened up into its operating position, it may be propelled eitherby sail or outboard motor (not shown). When under sail it is steered bythe sweep rudder 32, which is removed when an outboard motor is used onthe outboard rack 29. It will be noted that the craft has neithercenterboard nor leeboards, as the outboard planking panels 37 of the twohulls 13, 15 serve the purpose of minimizing slippage to leeward whenunder sail. Thus the extra structure and weight of such boards and theaccessory equipment necessary to sustain them are saved, with aresulting saving in cost, and a leaking centerboard trunk is avoided.The craft draws very little water without a centerboard and thereforecan sail almost anywhere. The reduced draft at the ends of the hulls 13,15 permits the hulls to pivot about their mid-points, as when comingabout, and the extra leverage provided by the sweep rudder 32 permitsthe craft to be readily spun about when changing tack or when otherwiserequired during maneuvering. This is also facilitated by the fact thatthe sweep rudder 32 (unlike a conventional rudder) can be pivoted out ofand into the water and used like a normal oar in the spinning procedure.

The tremendous beam-to-length ratio makes the craft most stable undersail so that capsize is virtually impossible. Also the great beamprovides far greater useful space and carrying capacity thanconventional craft of similar length.

The flexibility of the deck 17 allows each hull 13, 15

to adjust itself somewhat independently to wave formations, therebyimparting far less strain to the craft than that received by rigid typecatamarans. The foldability of the mast 27 permits that it, along withthe boom (not shown), sweep rudder 32, sail (not shown) and other gear,may be stored on the deck 17 within the folded craft. The greatamount ofspace available for storage within the folded craft may be seen inFigure 7. Because of the simplicity of the craft, it may be folded orunfolded in a matter of minutes. Also, because of this very simplicityof construction, the weight can be kept so low that the craft, whenfolded, may be placed easily upon a trailer or car top, or even on atwo-wheeled hand cart, for transportation. It should be noted that,although the hulls 13, 15 need not incorporate any frames as such, inthe smaller sizes of my craft, the gunwale coamings 47, the inboardsheer strakes 41, the transoms 39, and the outriggers 24 act as framesas they coact to stifien, strengthen and support the hulls, withouthowever adding more weight.

What I claim is:

1. A watercraft comprising a central deck member, first and second hullspivotally secured to the deck mem her along respective spacedsubstantially parallel pivot axes, each hull being pivotable about itspivot axis to an upright position alongside the deck member and to aninverted position over the deck member, and means to retain the hulls intheir upright positions, the first hull having a concavity, the hullswhen in their inverted positions being at least partly nested so thatthe second hull extends into the concavity of the first hull and thefirst hull is positioned at least partly over the second hull.

2. A watercraft as defined in claim 1 wherein the hull retaining meansinclude an outrigger swingably secured to the deck member, the outriggerbeing swingable to an extended retaining position and to a retractedposition, the outrigger when in its extended position retaining one ofthe hulls in its upright position and locking the hull against pivotingto its inverted position, and the outrigger when in its retractedposition permitting the hull to be pivoted to either its uprightposition or its inverted position.

3. A Water craft as defined in claim 1 wherein each hull includes oneside which is sufficiently vertically oriented that it acts to minimizeleeward movement of the craft in one leeward direction.

4. A water craft as defined in claim 1 wherein each hull includes aninner side and an outer side, the inner side having a greater dimensionfrom its upper edge to its lower edge than the outer side to permit thehulls to nest when in their inverted positions, and the outer sides whenthe hulls are in their upright positions being more nearly verticallydisposed than the inner sides to act to minimize leeward movement of thecraft.

5. A water craft as defined in claim 1 wherein each hull is V-bottomedand includes a keel and inner and outer sides secured to the keel, eachhull being asymmetrical in that the inner side is longer in a directionfrom keel to waterline than the outer side, and the outer side is morevertically disposed than the inner side to act as a leeboard.

6. A water craft as defined in claim 1 wherein each hull in transversecross section is V-shaped and includes an inner planking panel and anouter planking panel, the outer planking panel being positioned morenearly vertically than the inner planking panel to function as aleeboard.

7. A water craft comprising a central deck member, two hulls coupledrespectively to opposite sides of the deck member, each hull beingmovable to operating and non-operating positions, the hulls when intheir operating positions being upright on opposite sides of the deckmember and when in their non-operating positions one hull extending atleast partly between the other hull and the deck member, releasablemeans to retain the hulls in their operating positions and, uponrelease, to permit the hulls to be moved to their non-operatingpositions.

8. A water craft as defined in claim 7 wherein each hull has itsoutboard side disposed sufiiciently vertically to act as a leeboard.

9. A water craft as defined in claim 7 wherein the hulls when in theirnon-operating positions are positioned substantially over the deckmember.

10.A water craft as defined in claim 9, wherein the hulls when in theirnon-operating positions are at least partly nested one Within the other.

11. A water craft as defined in claim7, wherein the releasable meansinclude an outrigger pivotally secured to the deck member for pivotingabout a generally vertical pivot axis to a transverse position acrossone hull and to a longitudinal position over the deck member, and meansto secure the outrigger to the hull when in its transverse position.

12. A catamaran comprising a deck member and two hulls pivotally securedto the deck member, the deck member including a deck panel having someflexibility, two longitudinal stringers secured to the deck panel togive it some stiffness, two transverse braces secured to the deck panelto give it some stiffness, outriggers swingably secured to the crossbraces and swing able to transverse and longitudinal positions, theoutriggers in their transverse positions acting to lock the hulls intheir operating positions and in their longitudinal positions permittingthe hulls to be pivoted about a pivot axis over the deck member tofolded positions, each hull including an outer side provided with agunwale along its upper edge, said outer side being positionedsufficiently vertically to act as a leeboard, and an inner side providedwith hinge means which pivotally couple the inner side to the deckmember and provide a pivot axis adjacent the upper edge of the innerside, said inner side having a dimension from its pivot axis to the keelgreater than the dimension of the outer side from its gunwale to thekeel, the hulls when in their folded positions being at least partly oneabove the other and at least partly internested.

13. A hull for a folding catamaran comprising a keel, inner and outerplanking panels secured to the keel and drawn into curved configurationsand each extending in a generally longitudinal direction, a V-shapedtransom closing each end of the hull, a strengthening gunwale coamingalong the sheer of the outer planking panel, a relatively stiii sheerstrake along the upper edge of the inner planking panel, pivot hingemembers secured to the sheer strake and defining an axis about which thehull may be pivoted, the distance from the keel to the pivot axis beinggreater than the distance from the keel to the gunwale coaming.

14. A folding catamaran for car top portage comprising a central deckmember, two hulls hingedly coupled to the deck member, the hulls being;swingable inwardly over the deck member into folded positions, the hullswhen folded being at least partly one above the other, the lower hullbeing nested at least partly within the upper hull, the folded catamaranpresenting to the wind at least at one end an inclined leading aspectshaped to urge it downwardly on a car top upon which it is positionedfor portage, when traveling at relatively high speeds.

References Cited in the file of this patent UNITED STATES PATENTS596,685 Quist Jan. 4, 1898 1,625,579 Walters Apr. 19, 1927 2,464,957Wood Mar. 27, 1949 2,585,599 Tchetchet Feb. 12, 1952 2,588,084 BushfieldMar. 4, 1952 FOREIGN PATENTS 2,093 Great Britain Ian. 30, 1899

